Fujitsu FR81S User Manual
CHAPTER 8: DMA CONTROLLER (DMAC)
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : DMA CONTROLLER (DMAC)
FUJITSU SEMICONDUCTOR CONFIDENTIAL
32
5.1.3. Operations
This section explains DMAC operations.
This section explains the DMAC operations as follows.
(1) Channel status check
(2) Data transfer
Channel Status Check
Each DMAC channel status can be checked using the DCSRn register.
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When the channel operation is enabled (the channel is active), the DCSRn:CA bit is "1". When the
channel is stopped, its status is shown as "0".
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If data transfer terminates abnormally, the DCSRn:AC bit is set to "1".
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If data transfer is suspended by the transfer stop request, the DCSRn:SP bit is set to "1".
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When data transfer terminates normally, the DCSRn:NC bit is set to "1".
Data writing to the DCSRn:CA bit is ignored.
The DCSRn:AC, DCSRn:SP, and DCSRn:NC bits must be cleared before the DMA transfer is allowed
because these bits are not cleared automatically.
Data Transfer
The DMAC starts DMA transfer when the transfer source address and transfer destination address are set.
By receiving a transfer source read instruction, this controller reads the data, having the bit width
(8-bit/16-bit/32-bit) being set by DCCRn:TS, from the transfer source address, and temporarily stores it in
the data buffer inside of the DMAC. By receiving a transfer destination write instruction, the controller
writes the data temporarily stored in the DMAC into the transfer destination address.
Transfer Mode
The transfer mode has block transfer mode or burst transfer mode.
MB91520 Series
MN705-00010-1v0-E
331